Trends in mortality due to cancer in the US by age and county-level income, 1999-2015

: Disparities in cancer mortality by county-level income have increased. It is unclear whether these widening disparities have affected older and younger adults equally. National death certificate data were utilized to ascertain cancer deaths during 1999-2015. Average annual percent changes (AAPCs) in mortality rates and mortality rate ratios (RRs) were estimated by county-level income quintile and age (25-64 vs. ≥65). Among 25-64-year-olds, cancer mortality rates were 30% higher (RR = 1.30, 95% confidence interval [CI]:1.29-1.31) in the lowest vs. highest income counties in 1999-2001, and 56% higher (RR = 1.56;95%CI:1.55-1.57) in 2013-2015; the disparities among ≥65-year-olds were smaller but also widened over time (RR1999-2001:1.04,95%CI:1.03-1.05; RR2013-2015:1.14,95%CI:1.13-1.14). Widening disparities occurred across cancer sites. If all counties had the mortality rates of the highest income counties, 21.5% of cancer deaths among 25-64-year-olds and 7.3% of cancer deaths in ≥ 65-year-olds would have been avoided in 2015. These results highlight an ongoing need for equity-focused interventions, particularly among younger adults.